As described in particular in the patents U.S. Pat. No. 4,712,818, U.S. Pat. No. 4,583,910, U.S. Pat. No. 5,117,611, FR 2 494 214, NL 7708236 . . . , the current packing devices designed for the automatic filling of containers by means of superimposed layers of products, in particular fruits such as oranges, comprise mainly:
means for transporting the products which are capable, from a flow of products delivered in bulk, of dividing this flow into two separate streams, PA1 two separate feed stations suited to arranging each stream of products so that said products are aligned the ones behind the others in parallel rows, the products of each row, on a level with a feed station, being disposed in alternating positions relative to the products of the corresponding rows of the other feed station, PA1 a central packing station comprising means for positioning each container which are suited to provide support for said container for the purpose of filling it, PA1 gripping means capable of gripping alternately, square to each feed station, a number of products forming a layer with dimensions mating with the internal section of the container, and of placing this layer in said container so as to fill the latter by means of superimposed layers of products offset the ones relative to the others. PA1 each feed station comprises: PA1 the gripping means comprise: PA1 the suction means comprise a central suction unit connected to the suction tanks of the gripping heads, and switching members capable of depressurizing alternately the one or the other of the suction tanks, PA1 the means for activating the gripping members comprise members for detecting the bottom position of the means for vertical displacement of the gripping heads, which are disposed on a level with the packing station and are connected to the switching members so as to produce a halt in the depressurizing of the tank of the gripping head disposed in said bottom position. PA1 a longitudinal central conveyor belt for supplying a flow of products, PA1 two transverse conveyor belts extending between the downstream end of the central conveyor belt and the upstream ends of the conveyor belts of the feed stations, so as to form with the central conveyor belt a T-shaped transport line whose arms are formed by said transverse conveyor belts, which is suited to divide the flow of products into two streams, PA1 guiding members disposed above the transverse conveyor belts, which are suited to divert the products and delivering them towards the conveyor belts of the feed stations. PA1 a platform for raising the container which is in contact with the stop means, said stop means being capable of displacing said container between a top position, in which it is located above the plane of the conveyor, and a bottom position, in which it rests on this conveyor, PA1 means for expanding the upper edge of the container supported in top position by the lifting platform, which are capable of flattening themselves against the internal faces of the upper end of the lateral walls of this container, and of causing a perceptible expansion of said container. PA1 either in a position of minimum parting enabling said flaps, when a container is displaced towards its top position, to be induced to penetrate partially into this container without stressing the walls of the latter, PA1 or into a position of maximum parting in which said flaps each flatten themselves against a lateral wall of the container disposed in its top position, producing expansion of the latter.
Such packing devices have the advantage of being completely automated and of exhibiting a high filling rate. In addition, the filling of the containers is performed by means of layers of products disposed so as to be perfectly offset the ones with respect to the others, and the risk of damage to these products, particularly when the latter consist in fruits, during the handling and transport of the containers, is therefore dispelled.
These packing devices nevertheless have a major drawback resulting from the tiresome operations that have to be carried out on the occasion of a change in the size of products for packing, which change frequently arises when these products consist of fruits, such as oranges, that are sorted beforehand as a function in particular of their size. Although in fact certain devices, in particular those described in the patent U.S. Pat. No. 4,712,818, are provided with fixing devices permitting the rapid fitting and dismantling of a chamber bearing the gripping members, for the purpose of adapting the distribution of these gripping members to the distribution of the products as a function of their size, the operations for modifying the feed stations are for their part tiresome.
These feed stations comprise, in fact, parallel corridors each of which is capable of accommodating a row of products aligned the ones behind the others, and limit of travel slides disposed towards the end of each of these corridors and against which the first products of each row abut, the position of these slides being variable according to the various corridors so that the fruits occupying one and the same position in the various rows are aligned along axes secant to the longitudinal axis of these rows.
Consequently, any change in size makes it necessary not only to modify the width of the various corridors, but also to set the position of each slide in such a way as to obtain a satisfactory distribution of the products. It should be noted, in addition, that these operations can produce setting errors and contribute, by this very fact, to a reduction in output of the packing device due to the need to correct such errors.